Logical Query Processinghttp://www2.sqlblog.com/blogs/tamarick_hill/archive/2013/05/31/logical-query-processing.aspx&#160; When I first began working with SQL Server several years ago, one thing that really hung me up was, not understanding why I could reference an Alias column in certain parts of my query, but not in all parts of my query. To be more specific, whyenCommunityServer 2.1 SP2 (Build: 61129.1)